Searches the string haystack for the first occurrence of the string needle, limiting the length of the search to haystack_len.
a string.
the maximum length of haystack. Note that -1 is a valid length, if haystack is nul-terminated, meaning it will search through the whole string.
the string to search for.
a pointer to the found occurrence, or NULL if not found.
See Implementation
Searches the string haystack for the first occurrence of the string needle, limiting the length of the search to haystack_len.